You missed the number 1 reason: People buy new because it is a status symbol; in fact the car is second only to the house as the biggest status symbol most people own.
Is my brand-new Honda Fit more of a status symbol than my neighbor’s new-to-him certified pre-owned Mercedes SL500? I don’t think so.
I suspect it started when the expected life, and quality, of cars was much worse than today.
I just got a card looking to buy my 4 year old Prius for only $3,000 less than I paid for it. The used car market is a lot different that it used to be, since the price now reflects cost of ownership and quality.
Oh sure, that is likely. Cars lasted 3 years, 5 if lucky, and many people bought a new car every year or two.
I remember those cars. Back in the fifties and sixties odometers only went to 99,999.9 miles before rolling over to zero, and you were damn lucky to get there. These days 140,000 miles is probably the median. Mostly I credit corrosion protection, I had a 1968 Dodge Charger with a 318 engine that you couldn’t kill, but after only 8 years it had rusted so badly there were pieces falling off and the floorboards leaked so badly water would hit the roof liner when you drove through puddles.